Data mode


Sign up

Copy permalink to share

Podostemum ceratophyllum Michaux. Threadfoot, Riverweed, Riffleweed. Phen: May-Jul. Hab: Attached to rocks and dams in rapidly or slowly flowing water. Dist: NS, ME, and QC south to sw. GA, s. AL, s. MS, se. LA (Florida parishes), AR, and w. TN; disjunct in the Ozark-Ouachita Highlands of w. AR and e. OK; Dominican Republic; Honduras.

Origin/Endemic status: Native

Taxonomy Comments: Fehrmann, Philbrick, & Halliburton (2012) demonstrated very low genetic diversity in the populations of Podostemum ceratophyllum north of the glacial maximum, in the Ozark-Ouachita Highlands, and in Central America, and high genetic diversity in the portion of the unglaciated southeast east of the Mississippi River.

Synonymy: = Ar, C, F, FNA6, G, K1, K3, K4, NE, NY, Pa, RAB, Tn, Va, W, WV, Graham & Wood (1975); = Podostemon ceratophyllum – GW2, Tx, orthographic variant; > Podostemon abrotanoides Nutt. – S, S13; > Podostemon ceratophyllum – S, S13, orthographic variant

Show in key(s)

Show parent genus

Wetland Indicator Status:

  • Atlantic and Gulf Coastal Plain: OBL
  • Eastern Mountains and Piedmont: OBL
  • Midwest: OBL
  • Northcentral & Northeast: OBL

Heliophily ?: 8

Your browser does not support SVGs

Hover over a shape, letter, icon, or arrow on the map for definition or see the legend.

image of plant© Gary P. Fleming | Original Image ⭷
image of plant© Alan Cressler: Podostemum ceratophyllum, Congaree River, Richland County, South Carolina 1 by Alan Cressler source | Original Image ⭷
image of plant© Alan Weakley source | Original Image ⭷


See something wrong or missing on about Podostemum ceratophyllum? Let us know here: (Please include your name and email if at all complicated so we can clarify if needed.) We greatly appreciate feedback, and will include updates from you in our next webapp update, which can take a few months.

Cite as...